Explanation:
Nestled within the dusty arms of the large
spiral galaxy Andromeda (M31),
the star cluster
NGC 206 is one of the largest
star forming regions known in our local group of galaxies.
The beautiful bright blue stars
of NGC 206 betray its youth -
but close, systematic studies of variable
stars in and
around NGC 206 will also accurately reveal its distance.
Astronomers
are searching for variable stars in NGC 206,
particularly pulsating stars known as
Cepheids and
eclipsing binary star systems.
Distances for these types of stars can be effectively determined by
following the
periodic changes in their brightness and spectra.
About 3 million light-years away,
an accurately known distance to NGC 206 and
thus M31 is
critical to the larger understanding of galaxy formation, galaxy evolution,
and ultimately
the distance scale of the Universe.